It is common that many electronic parts are mounted on a main board mounted in a portable apparatus. From among the mounted electronic parts, an RF block for transmitting and receiving wirelessly, that is, an RF transceiving circuit exists. In the case of the RF transceiving circuit, a shielding structure is mounted therein in various ways to shield from electromagnetic noise to minimize mutual interference of various noises. In recent years, a shielding can of a Surface Mounting Device (SMD) type serving as a shielding structure for the RF transceiving circuit is used to maximize productivity and also reduce a size.
As the portable apparatuses have been enhanced with higher performance, the circuit structure of the portable apparatuses has become complicated and the packing density of parts has increased. Therefore, the packing and wiring density of the main RF electronic parts including a transceiver, a transceiver power amplifier, a Low-Noise Amplifier (LNA) also increases.
For the reasons described above, various problems arise according to characteristics or arrangement of electronic parts, a wiring condition, or a GND condition. In particular, when an RF transceiver and an RF transceiver power amplifier are mounted in a single shielding structure close to each other, power outputted from the RF receiver power amplifier may use the shielding structure as a feedback path and thus may be led to the RF transceiver again. In this case, a phase-related characteristic of a transmission signal of the RF transceiver or an Error Vector Magnitude (EVM)-related or neighboring channel noise characteristic may be degraded.